Three babySumatran tigers were born at the Los Angeles Zoo Aug. 5 to experienced mother Lulu. The species is classified as endangered, so Lulu’s latest litter marks a big step toward the conservation of the species.

Unfortunately, not all of the cubs were able to survive.

“As excited as we are in this moment of celebration, we are equally saddened to announce that one of the three tiger cubs has unexpectedly passed,” said zoo director John Lewis. “This is the third litter at the L.A. Zoo from our experienced mother who has successfully raised a total of five cubs. While the loss of this cub is unfortunate, we plan to continue to share the growth of the two cubs with our community until they are introduced to their exhibit. I hope you’ll share the adventure with us.”

Photos: Tad Motoyama

The cubs currently spend most of their time with their mother, but they also get daily visits from their keepers, in order to foster a relationship that will ease the process of routine veterinary checkups.